One second, Regulus Black was competing with the Inferi in the lake and holding his breath. The next second, he was on the Hogwarts Express in 1991, using a new identity to return to the ivory tower without the mysterious man. He was busy rescuing his brother from Azkaban, and had to take care of his nephew and brother's godson... Regulus said that he was still very tired after resurrecting his life.
